1. Field of the Invention
The present invention is generally directed to the field of roofing materials and is more particularly directed to a molded roofing unit formed from a fiber-reinforced plastic, uniquely configured to simulate conventional roofing products and having high hail resistance, wind resistance, fire resistance, ease of installation, and aesthetic appeal.
2. Description of the Related Art
A number of different roofing products have been developed and used over the years to cover and protect a building. Various factors may be considered in choosing a roofing product including the cost of the product, ease of application or installation, and appearance. Equally important is the performance or weatherability of the roofing product, meaning its ability to withstand cold, rain, hail and wind and to shed snow and endure ice buildup without significant damage. Fire resistance is another important consideration and is increasingly being identified by insurance companies as a desirable attribute for lowering insurance premiums.
Clay tile, concrete, and slate roofs are distinctive and aesthetically pleasing in appearance such that even the "best" neighborhood associations approve the use of these roofing products. Clay, concrete, and slate also generally withstand wide ranging temperatures, rain, snow and wind, and are relatively fire resistant. However, these materials can be expensive, may be susceptible to damage from hail and foot traffic, and the installment is generally labor intensive. Further, slate, concrete, and clay roofing products can be heavy, such that reinforced structures may be required to support their weight.
Wood shakes are also generally approved by most neighborhood associations for residential use and are less expensive than clay, concrete, or slate roofs. Wood shakes are easier to install than clay, concrete, and slate roofs, although measuring and/or squaring of the individual shakes during installation can prove time consuming and the shakes may split during shipment or installation, thereby increasing the overall cost of materials. Wood shakes are also susceptible to hail damage and generally cannot attain a high degree of fire resistance without costly treatment. Wood shakes are often perceived as catching fire relatively easily in the presence of lightening, sparks from fireworks, or other airborne flames. When exposed to water, wood roofing materials may swell or curl along the edges, thereby providing a protruding surface for winds to catch.
Asphalt shingles, also known as composition roofing, are less expensive than wood roofing and are relatively easy-to-install. However, asphalt roofing products generally do not provide the sought after appearance of wood shakes, slate, clay, or tiles, and therefore are not approved for use in some residential areas with high-priced homes. While asphalt roofing is resistant to fire, it is generally prone to hail and wind damage and may need to be replaced over time due to brittling and cracking from exposure to the elements.
Due to the inadequacies of conventional roofing products, various attempts have been made in the past to develop plastic-based roofing materials that possess the desired combination of physical properties, low cost, aesthetic appeal and ease of installation.
For example, U.S. Pat. No. 5,635,125 to Ternes et al. discloses arelatively flat molded shingle formed of ground-up recycled polyvinyl chloride (PVC) particles and wood sawdust particles. U.S. Pat. No. 5,615,523 to Wells et al. discloses a relatively flat shingle panel comprising a resinous plastic material combined with a large amount of filler.
While these prior plastic and/or composite roofing products heretofore developed for replacing conventional roofing products are suitable for such purposes, none of the products developed to date have fully met the desires of the industry. These prior products do not provide the desired aesthetic attributes, nor superior physical properties. Thus, a need remains in the art for an improved plastic composite roofing product that may be made from relatively safe polyolefin materials, recycled and/or virgin, having high impact resistance, wind resistance and fire resistance, with an aesthetically pleasing appearance and that may serve as a drop-in replacement for traditional roofing products at a reasonable cost. To this end, one of the primary objects of this invention is to provide a polyolefin roofing unit reinforced by partially delignified fibers, in which the fibers bind to the plastic to provide a greater degree of wind resistance and impact resistance than previously known in plastic roofing products and with costs comparable to traditional roofing products.
It is a further object of the invention to provide a lightweight fiber-reinforced plastic roofing composition and unit formed therefrom of sufficient strength, stiffness, and impact resistance to withstand all types of outdoor conditions, including hail, high winds, and foot traffic.
It is yet another object of this invention to provide a fiber-reinforced plastic roofing composition that can use post consumer and/or post industrial plastics.
It is a further object of this invention to provide a fiber-reinforced plastic roofing composition that uses waste agricultural and/or forestry materials.
It is another object of this invention to provide a fiber-reinforced plastic roofing composition and unit formed therefrom with superior product longevity over typical roofing materials.
It is a further object of this invention to provide a fiber-reinforced plastic roofing unit with the appearance of slate, tile, or wood roofing.
It is another object of the invention to provide a fiber-reinforced plastic roofing composition and unit formed therefrom that is resistant to pests.
It is still another object of the invention to provide a fiber-reinforced plastic roofing composition and unit formed therefrom of sufficient stiffness and strength to be installed on solid or spaced sheathing roof deck.
It is a further object of this invention to provide a fiber-reinforced plastic roofing unit that can serve as a drop-in replacement for wood shake shingles.
It is still another object of this invention to provide a fiber-reinforced plastic roofing unit with a configuration that provides increased hail and wind resistance properties.
It is yet another object of this invention to provide a fiber-reinforced plastic roofing unit that sheds snow and thereby reduces snow buildup.
It is still another object of this invention to provide a fiber-reinforced plastic roofing unit that minimizes damage from ice buildup.
It is a further object of this invention to provide a fiber-reinforced plastic roofing composition and unit formed therefrom that wicks little or no water.
It is another object of this invention to provide a molded fiber-reinforced plastic roofing unit that utilizes a minimal amount of materials and that solidifies quickly after the molding process.
It is another object to create a fiber-reinforced plastic roofing composition and unit formed therefrom with greater solvent, detergent, and other chemical resistance than metal, PVC, or asphalt roofing products.
It is yet another object of this invention to provide a fiber-reinforced plastic roofing composition and unit formed therefrom with a Class C or higher fire rating.
It is a further object of the invention to provide a fiber-reinforced plastic roofing unit that produces less waste in the creation and installation of the material as compared to cedar shakes.
It is still another object of the invention to provide a fiber-reinforced plastic roofing composition and unit formed therefrom wherein the reinforcing fiber is not highly abrasive.
It is yet another object of this invention to provide a fiber-reinforced plastic roofing composition and unit formed therefrom with excellent nail-holding capacity.
It is yet another object of this invention to provide fiber-reinforced plastic roofing composition and unit formed therefrom that is 100% recyclable.
It is yet another object of this invention to conserve the use of industrial resources.